Method for detecting inconsistency of single cells in vehicle battery, device and medium

Abstract

Disclosed are a method and a device for detecting inconsistency of single cells in vehicle battery, and a medium. The method includes obtaining current battery data for a vehicle under test, determining whether the current battery data corresponds to a charging or discharging condition, and separately evaluating the presence of inconsistency in cells under each condition. This enables distinct detection for charging and discharging conditions, thereby enhancing detection accuracy.

What is claimed is: 
     
       1. A method for detecting inconsistency of single cells in a vehicle battery, comprising:
 obtaining, by a processor, current battery data for a to-be-tested vehicle, wherein the current battery data comprises charge-discharge status, single cell voltages, battery current, and state of charge (SOC); 
 if the current battery data is determined to correspond to a charging condition based on the charge-discharge status, extracting, by the processor, target analysis data from the current battery data based on the SOC at various time points, by using a first warning model associated with the charging condition; determining, by the processor, whether cell inconsistency exists in the to-be-tested vehicle by a current mean voltage drop among the single cells corresponding to the target analysis data; and 
 if the current battery data is determined to correspond to a discharging condition based on the charge-discharge status, extracting, by the processor, the target analysis data from the current battery data based on the battery current and the SOC at various time points by using a second warning model associated with the discharging condition; determining, by the processor, whether the cell inconsistency exists in the to-be-tested vehicle by a current voltage differential between single cells at adjacent time points corresponding to the target analysis data; 
 wherein, determining whether the cell inconsistency exists in the to-be-tested vehicle by a current mean voltage drop among the single cells corresponding to the target analysis data comprises: 
 determining, by the processor, a historical mean voltage drop for each historical charging condition based on historical battery data of a preset number of historical charging conditions nearest to current moment; 
 constructing, by the processor, a mean drop change curve based on the historical mean voltage drop for each historical charging condition, a time elapsed from a first charging condition to the each historical charging condition, a current mean voltage drop for a current single charging condition, and a time elapsed from the first charging condition to the current single charging condition; determining, by the processor, a first slope of the mean drop change curve; wherein, the first slope reflects a rate of change of the mean voltage drop in the continuous charging conditions; 
 if the first slope is greater than a second preset threshold, and a difference between maximum and minimum values of the historical and current mean voltage drops is greater than a third preset threshold, determining, by the processor, the existence of cell inconsistency under the continuous charging conditions for the to-be-tested vehicle, generating a second warning signal, and transmitting the second warning signal to an associated terminal of the to-be-tested vehicle; 
 wherein, determining whether the cell inconsistency exists in the to-be-tested vehicle by the current voltage differential between the single cells at the adjacent time points corresponding to the target analysis data comprises: 
 determining, by the processor, a historical maximum coefficient of variation (CV) and a historical maximum CV difference for each discharging condition based on the historical battery data for a preset number of the historical discharging conditions nearest to the current moment; 
 constructing, by the processor, a CV difference change curve based on the historical maximum CV difference, a time elapsed from the first discharging condition to each historical discharging condition, a current maximum CV difference for a current single discharging condition, and a time elapsed from the first discharging condition to the current single discharging condition; and determining, by the processor, a second slope of the CV difference change curve; wherein, the current maximum CV difference is a difference between a current maximum CV and a current minimum CV; the current CV describes the degree of cell voltage fluctuation of the battery under the current discharging condition, and the second slope reflects the rate of change in the degree of fluctuation between the single cells under the continuous discharging conditions; 
 if the second slope is greater than a sixth preset threshold, and a maximum value among each historical maximum CV and the current maximum CV is greater than a seventh preset threshold, determining, by the processor, the existence of the cell inconsistency in the to-be-tested vehicle under multiple discharging conditions, generating a second warning signal, and transmitting the second warning signal to the associated terminal. 
 
     
     
       2. The method according to  claim 1 , wherein, extracting the target analysis data based on the SOC at various time points in the current battery data comprises:
 obtaining a first preset charge analysis range; 
 based on the first preset charge analysis range, selecting time points at which the SOC is within the first preset charge analysis range in the current battery data; and 
 constructing the target analysis data based on the cell voltages at the selected time points. 
 
     
     
       3. The method according to  claim 1 , wherein, extracting the target analysis data based on battery current and the SOC at various time points in the current battery data comprises:
 obtaining a second preset charge analysis range and a preset current analysis range for current analysis; 
 based on the second preset charge analysis range and the preset current analysis range, selecting time points at which the SOC is within the second preset charge analysis range and the battery current is within the preset current analysis range; and 
 constructing the target analysis data based on the cell voltages at the selected time points. 
 
     
     
       4. The method according to  claim 2 , wherein, determining whether the cell inconsistency exists in the to-be-tested vehicle by a current mean voltage drop among the single cells corresponding to the target analysis data further comprises:
 for each time point in the target analysis data, determining the maximum mean voltage drop between single cells based on the cell voltages at the time point; 
 determining the current mean voltage drop corresponding to the target analysis data based on the maximum mean voltage drop at each time point; 
 determining whether the current mean voltage drop is greater than a first preset threshold; and 
 if yes, confirming the presence of inconsistency in single cells of the to-be-tested vehicle under the current single charging condition, generating the first warning signal, and transmitting the first warning signal to the associated terminal corresponding to the to-be-tested vehicle. 
 
     
     
       5. The method according to  claim 3 , wherein, determining whether the cell inconsistency exists in the to-be-tested vehicle by a current voltage differential between single cells at adjacent time points corresponding to the target analysis data further comprises:
 for each single cell, based on the cell voltages at various time points corresponding to the target analysis data, determining the current voltage differentials between the single cells at adjacent time points; 
 based on each of the current voltage differentials, determining a current voltage coefficient of variation (CV) for each cell; 
 determining a current maximum CV and a current maximum CV difference among all cells based on the current voltage CV of each cell; and 
 if the current maximum CV is greater than a fourth preset threshold and the current maximum CV difference is greater than a fifth preset threshold, determining the presence of inconsistency in the single cells in the to-be-tested vehicle under the current single discharging condition, generating the first warning signal, and transmitting the first warning signal to the associated terminal of the to-be-tested vehicle. 
 
     
     
       6. The method according to  claim 5 , wherein determining the current voltage CV for each cell based on the various current voltage differentials comprises:
 determining a mean voltage differential of each current voltage differential; 
 determining a voltage differential standard deviation based on each current voltage differential and the mean voltage differential; and 
 determining the current voltage CV for the single cell based on the mean voltage differential and the voltage differential standard deviation. 
 
     
     
       7. An electronic device, comprising:
 a processor and a memory, 
 wherein the processor, by invoking a program or instruction stored in the memory, is configured to execute the steps of the method according to  claim 1  for detecting inconsistency of single cells in a vehicle battery. 
 
     
     
       8. A non-transitory computer-readable storage medium, storing a program or instruction, wherein the program or instruction, when executed by a computer, causes the computer to perform the steps of the method according to  claim 1  for detecting inconsistency of single cells in a vehicle battery.